| La Grosse Décharge Ouest | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Canada |
| Subdivision Type2: | Province |
| Subdivision Name2: | Quebec |
| Subdivision Type3: | Region |
| Subdivision Name3: | Capitale-Nationale |
| Subdivision Type4: | Regional County Municipality |
| Subdivision Name4: | Charlevoix Regional County Municipality |
| Subdivision Type5: | City |
| Subdivision Name5: | Baie-Saint-Paul |
| Length: | 7.7km (04.8miles) |
| Source1: | Côté Lake |
| Source1 Location: | Baie-Saint-Paul |
| Source1 Coordinates: | 47.5109°N -70.7063°W |
| Source1 Elevation: | 629m (2,064feet) |
| Mouth: | Rivière des Mares (Gouffre River tributary) |
| Mouth Location: | Baie-Saint-Paul |
| Mouth Coordinates: | 47.4828°N 70.6416°W |
| Mouth Elevation: | 350m (1,150feet) |
| Tributaries Left: | (from the mouth) Brook, La Grosse Décharge Est |
| Tributaries Right: | (from the mouth) Six streams. |
La Grosse Décharge Ouest is a tributary of the west bank of the upper part of the rivière des Mares, flowing entirely in the town of Baie-Saint-Paul, in the Charlevoix Regional County Municipality, in the administrative region of Capitale-Nationale, in the province from Quebec, to Canada.
This valley is mainly served by the Seminary path which runs along the south side of this watercourse. Forestry is the main economic activity in this valley; recreational tourism, second.
The surface of La Grosse Décharge Ouest is generally frozen from the beginning of December until the beginning of April; however, safe circulation on the ice is generally done from mid-December to the end of March. The water level of the river varies with the seasons and the precipitation; the spring flood generally occurs in April.
The Grosse Décharge Ouest rises at the mouth of Côté lake (length: ; altitude:). This lake is enclosed between the mountains whose summit reaches at to the northeast; another peak reaches at to the southwest. The mouth of this lake is located at:
From its source, the course of La Grosse Décharge Ouest descends from the mountain on with a drop of, according to the following segments:
The Grosse Décharge Ouest pours into a bend on the west bank of the Mares river in Baie-Saint-Paul. This mouth is located at:
From the mouth of La Grosse Décharge Ouest, the current descends on the course of the Mares river; then on with a drop of following the course of the Rivière du Gouffre which flows into Baie-Saint-Paul in the Saint-Laurent river.[1]
This toponymic designation appears on the map "Domaine forestier du Séminaire de Québec", 1955-01.
The toponym "La Grosse Décharge Ouest" was formalized on March 25, 1997 at the Place Names Bank of the Commission de toponymie du Québec.[2]